There is a bug with the ACM BORE mode and JHMCS.
Without turning the JHMCS on, pressing DGFT and TMS-up behaves as expected: radar scans the boresight zone.
Turning JHMCS on will enable JHMCS SLAVE. Pressing TMS-up will now slave the radar to where you are looking (see azimuth & elevation carets on CMFD) and turn on emissions. This is unexpected behavior: the manual states the radar will automatically pick up the first target inside the ACM BORE symbol ('egg') without the need for TMS-up.
Pressing TMS-down will re-center the radar and enable 'true' BORE mode. This can always be used to re-center, even in bugged state.
Turning off JHMCS with the rotating knob and then pressing TMS-up will slew the radar down and left ([0,0] coordinates?). This must be a bug, and puts the aircraft in a 'bugged' state. From here on, TMS-up will never enable non-JHMCS ECM BORE as expected. Turning off the JHMCS with DMS-down will repeat the behavior as if it was still on, whether in bugged state or not.
I have included a track that displays the issue. Watch the carets on the CMFD. {actions: DGFT toggle > TMS-up (good result) > JHMCS on > TMS-up (radar offset from bore) > TMS-down (re-center ACM BORE) > JHMCS off > TMS-up (carets show left/down)}
As for the other ACM modes: I haven't found any problems with those. Keep in mind the radar still has to perform a couple of sweeps (see carets), so acquisition is usually not instantaneous. F-16 ACM JHMCS bug.trk